643692408 has 32 divisors (see below), whose sum is σ = 1609866960. Its totient is φ = 214479360.

The previous prime is 643692391. The next prime is 643692451. The reversal of 643692408 is 804296346.

It is a happy number.

It is a super-2 number, since 2×643692408² = 828679832233676928, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 643692408.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97038 + ... + 103458.

Almost surely, 2^643692408 is an apocalyptic number.

It is an amenable number.

643692408 is an abundant number, since it is smaller than the sum of its proper divisors (966174552).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643692408 is a wasteful number, since it uses less digits than its factorization.

643692408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10607 (or 10603 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 42.

The square root of 643692408 is about 25371.0939456697. The cubic root of 643692408 is about 863.4280014586.

The spelling of 643692408 in words is "six hundred forty-three million, six hundred ninety-two thousand, four hundred eight".